What are Power Steering Pumps and How Do They Work?

The power steering pumps were introduced to reduce the efforts of the driver and give them a more pleasant experience while driving. They put the fluid pressure in to use to assist the driver in turning the front wheels.

Let’s look at power steering pumps in detail and understand their working, types, and signs of malfunction.

The power steering pump works on the principle of hydraulics, pushing the fluid into the steering gearbox. This fluid, in turn, assists the wheels of a vehicle. When a driver takes a turn by turning the steering wheel, the small ports open in the steering shaft through which high-pressure fluid rushes in and assists in turning the wheels. 

To function properly, the power steering pump needs a special type of fluid called the power steering fluid which is changed periodically, generally after 40,000 miles of usage.

For better understanding, we have simplified the working mechanism into 3 sections. Let’s go through them:

Before Steering Pump

Your car has a container under the hood that contains the power steering fluid. Whenever the fluid is needed, it is sucked out through this power steering fluid tank. Through the rubber hoses, it reaches the power steering pump. 

An engine belt is put around the rotating crankshaft, which helps it connect to the power steering pump pulley. As soon as the car is started, the belt pulls onto the pump pulley, and consequently, the power steering pump starts spinning.

Within Steering Pump

Here, the main work is done by the centrifugal force. With the help of this force, the vanes are pushed to the outside against the housing.

The centrifugal force is so strong that tiny chambers are formed that trap the steering fluid. The tiny chambers follow the rotation of the rotor. This increases the pressure of the fluid.

After Steering Pump

At this stage, the high-pressure hydraulic fluid is moved to the two chambers of the steering rack. This distribution is done so that one of the chambers gets more than the other. 

This fluid provides the power to assist and makes your steering wheel feel lighter. After the work is done, the fluid follows the same path and returns to the power steering fluid reservoir.

Basically, 4 types of power steering pumps mainly differ in the design of the fins which move the steering fluid inside the pump:

1. Vane Power Steering Pump

The vane power steering pump is a key component found in many modern cars' power steering systems. Its purpose is to assist the driver in turning the vehicle by applying hydraulic pressure to the steering mechanism. The pump is typically driven by the engine through a belt or other mechanical means.

2. Roller Power Steering Pump

Roller power steering pumps play a crucial role in enhancing the driving experience of modern cars. These pumps are designed to provide precise and effortless steering control, making handling the vehicle smoother and easier. 

One of the primary functions of the roller power steering pump is to supply pressurised hydraulic fluid to the power steering gear or rack.

3. Slipper Power Steering Pump

Also known as variable displacement pumps, they supply pressurised hydraulic fluid to the steering system, reducing the effort required to turn the wheels and enabling smooth manoeuvrability. 

The slipper power steering pump uses hydraulic pressure generated by an engine-driven belt to assist the driver in steering. As the driver turns the steering wheel, a series of interconnected fluid chambers within the pump adjusts the flow rate of the hydraulic fluid according to the demand.

4. Gear Power Steering Pump

In this type of power steering pump, the gears rotate inside and create a void that is filled with fluid. Now, this fluid is carried to the discharge side of the pump, where the meshing of the gears displaces it.

Let us look at some of the failure symptoms that will help you to identify any defect as soon as possible: 

• Whining or squealing noise while turning the wheel: It could either be due to a leak in the power steering pump, or the level of the fluid inside has become too low to be perfectly functional.
• The steering wheel gets stiff: Along with getting slow, your steering wheel can become stiff if your power steering pump fails. 
• Squealing noise while starting the vehicle: If your power steering pump fails, you might hear squealing noises when starting the vehicle and taking sharp turns. 
• The steering wheel is slow to respond: This is generally observed while turning a corner. If your power steering pump is on the verge of getting damaged, your steering will respond slowly to all the steering wheel inputs you are making.
• Groaning sounds: If your power steering pump lacks fluid, it will eventually start making groaning noises, worsening with time. Along with damaging your power steering pump, a lack of fluid will also affect the whole system, including the steering rack and lines.

The main factor that drives power steering lies within the power steering pump. So, you should always look out for your power steering pump and keep it in perfect working condition.